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© Novática Information Technologies for Visually Impaired People Figure 4: Transmission of Information by Dorsal or Ventral Stimulation. (although such a claim may be optimistic). Later other devices based on this principle were marketed, such as the "Visotoner" or its subsequent, more developed version, the "Stereotoner". It worked by means of a camera that projected an image onto an array of photo-receptors, each of which was associated with a rising or falling frequency depending on the position of the image. By passing the camera over a line of text a user would hear sounds representing the shape of each letter; for example the letter "v" would be represented by a tone that started high, then fell, and then rose again. Mauch Labs. Inc. ceased to manufacture these devices in 1977. Access to Written Information Braille The most commonly used method of reading for the blind is braille, invented in 1827 by Louis Braille in France when he was just 18 years old. It consists of a binary information system using a cell of six raised dots (2x3) which is well adapted to tactile exploration. A well trained blind person can achieve reading speeds akin to those of sighted people. The main drawbacks to the system was the space it occupied, its difficulty to learn, and the cost of producing texts. It was an indirect system of access to the written word insofar as it required someone else to manually transcribe the text (although a number of copies could be made at the same time by putting two or three sheets in at the same time and pressing harder). In order to make reading faster and save space, some countries developed a kind of shorthand braille. There are specific coding systems to transcribe music scores or mathematical texts, which need to overcome the problem caused by the fact that braille is a linear system and music and maths require multi-dimensional information to be represented (matrices, fractions, five line staves). This information is represented by a system of operators and parentheses. Reproduction difficulties became a thing of the past with the appearance of the braille printer and the thermoformer – a kind of embossing photocopier. The First Refreshable Braille Devices In the mid seventies O. Tretiakoff invented an electronic system of refreshable braille on a 12 character display. By combining this display with a and audio cassette machine and a 6-key braille keyboard he produced an innovative device: the Digicassette. The braille was recorded on a cassette and could be read on the 12 character braille display (which was later increased to 20). This system made copying easy and solved the problem of the sheer volume to be stored. Later another US company came up with another, similar system, the VersaBraille (see Figure 6), which was equipped with a serial interface that allowed it to be connected to a computer. The early cassette based recording systems of Digicassette and VersaBraille were later upgraded to floppy disk. These computer connectable refreshable braille displays represented a major step towards Internet accessible systems. Generation of Interface Devices Until relatively recently the quality of speech synthesis was too poor to be used in assistive technology for the blind. Today that problem no longer exists and an ever increasing number of blind people are turning to this solution, which is not incompatible with Braille and, while it falls short in some areas, has some other very interesting advantages such as ease of access, ease of indexing, and the possibility of increasing reading speed. Today speech synthesis is a cheap and simple way of electronically accessing any text document. The refreshable braille systems used in Digicassette and VersaBraille paved the way for modern day devices employed as a means of accessing computerized systems directly via a braille interface (see Figure 7). Today practically all printed information is transmitted through electronic media which, once legal and administrative problems have been overcome, allows direct access either by speech synthesis or by braille. Figure 5: Use of the Optacon. UPGRADE Vol. VIII, No. 2, April 2007 7
Information Technologies for Visually Impaired People This means that we have to take the needs of blind people into consideration when generating Web documents or pages. We need to take into account and respect W3C – WAI (Web Accessibility Initiative, ) recommendations to ensure that Web sites are accessible to everyone. A lack of awareness of these basic rules often prevents access to this type of information. Webmasters need to be aware of these initiatives and learn how to provide simple options for visually impaired people (contrast inversion, page amplification, etc.) It is more a problem of culture and unawareness than a lack of willingness so any information in this regard can only be welcome. Advances in Form Recognition The first reading machine based on intelligent character recognition was designed by Kurzweil who in the early eighties marketed a device that enabled blind people to access printed text automatically. It was a machine (like a large photocopier) which processed an image and outputted a speech synthesis in English. It was specifically designed for the blind and its high price meant that its use was mainly limited to specialized centres and libraries . More recently, thanks to the widespread use of office applications, the cost of hardware and software has come down so much (computer, scanner, OCR package, speech synthesis or braille line) that it is now a reasonable option in terms of achieving direct access to the printed word. Moving towards the present day, we should look at such inventions as the KNFB reader, also invented by Kurzweil, which is the first portable automatic reading device to read printed texts. It is based on a combination of numerical photography, PDA, and speech synthesis with a considerable memory. The device detects the edges of the document, indicates when the photo can be taken, and in a matter of seconds the text can be heard. These small computers equipped with cameras can also be used to identify everyday objects; cans of drink, caned foods, medicines, etc. Low Vision The definition of blindness that we saw earlier involves Figure 7: Refreshable Braille Interface Device. Figure 6: VersaBraille. the total absence of vision, but in many cases the use of residual vision is also an option, provided that the right equipment is available. From conventional magnifying glasses to electronic magnifiers sometimes linked to a computer and character recognition systems, there are solutions available to help those with low vision access information. Depending on the nature of the residual vision, such devices can allow users to alter the presentation, colour, size, etc. of the text they wish to read. 3 Conclusion The purpose of this brief historical overview is to introduce the subject of this edition and give readers a better understanding of the assistive products available to help the blind and partially sighted integrate into the information society and achieve autonomy. In the following articles readers will be able to see the current trends, the state of the art, the direction that research is taking, and the developments we can expect in the matter of assistive technology. Two clear trends can be identified: A specific development, the need for which arises at a specific moment in time, such as braille displays. The use of general purpose technologies that can be developed as technology advances. If it is impossible to avoid using special interfaces, it would seem logical to ensure that such devices are produced in such a way as to be integratable with conventional technology by using standard connection methods and protocols. Otherwise the result will be products that are too costly, hard to maintain, and with a tendency to become quickly obsolete, to the consequent frustration of their users. Thus, the development of general purpose OCR, with its falling cost and increasing reliability, is causing information access devices of a more special purpose nature to gradually disappear. Digicasette, VersaBraille, Optacon, Stereotoner and other such devices have given way to an ever changing information technology and an (accessible?) Internet with specially adapted but minimalist interfaces that integrate perfectly and make use of existing general purpose systems. Translation by Steve Turpin 8 UPGRADE Vol. VIII, No. 2, April 2007 © Novática
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